Figure 4. Treg Ablation Impairs Muscle Regeneration after Wounding.

Eight-week-old Foxp3⁻DTR⁺ or DTRT⁻ littermates were injured with Ctx and treated with DT to induce Treg depletion.

(A and B) Flow cytometry of Treg and myeloid-lineage population, 7 days postinjury. Numbers in (A) refer to % CD4⁺ T cells that are Foxp3⁺, and numbers in (B) refer to % Ly6c^−/lo or Ly6c^hi of CD11b⁺ cells.

(C) Hematoxylin and eosin (H&E) staining of muscle sections 7 days after Ctx injury. Representative of at least three experiments. Original magnification ×100.

(D) Left: fibrosis detection by Gomori trichrome staining of muscle sections 13 days after injury. Collagen stained in blue. Representative examples of seven DTR⁺ and seven DTR⁻ mice. Original magnification ×200. Right: summary quantification.

(E) Left: H&E staining of muscle sections 7 days after cryoinjury. Original magnification ×25 (left) and ×100 (middle and right). Representative examples of six samples. Right: quantification of regenerative fibers per mm² of injured area. ***p < 0.001.

(F) Clonal myogenesis assays of satellite cells from uninjured or day 4 Ctx-injured muscles. Percent of wells seeded that showed a myogenic colony at day 5. Summary of six clonal assays *p < 0.05; **p < 0.01.

(G) Left: FC/FC plot of gene expression values in muscle 4 versus 8 days after Ctx-induced injury in mice without (DTR⁺) or with (DTR⁻) Tregs. Highlighted in different colors are sets of genes described in the text. Right, representative examples of genes in each highlighted set.

See also Figure S3 and Table S3.